Conjugated polymers

#The invention relates to novel conjugated polymers containing repeating units comprising a halogenated benzene ring, a silolobithiophene moiety, and a benzofused heteroaromatic moiety, to methods for their preparation and educts or intermediates used therein, to polymer blends, mixtures and formulations containing them, to the use of the polymers, polymer blends, mixtures and formulations as organic semiconductors in organic electronic (OE) devices, especially in organic photovoltaic (OPV) devices and organic photodetectors (OPD), and to OE, OPV and OPD devices comprising these polymers, polymer blends, mixtures or formulations.

#Organic semiconducting (OSC) materials are receiving growing interest mostly due to their rapid development in the recent years and the lucrative commercial prospects of organic electronics.

#One particular area of importance is organic photovoltaics (OPV). Conjugated polymers have found use in OPVs as they allow devices to be manufactured by solution-processing techniques such as spin casting, dip coating or ink jet printing. Solution processing can be carried out cheaper and on a larger scale compared to the evaporative techniques used to make inorganic thin film devices. Currently, polymer based photovoltaic devices are achieving efficiencies above 8%.

#The polymers of the present invention are easy to synthesize and exhibit advantageous properties. They show good processability for the device manufacture process, high solubility in organic solvents, and are especially suitable for large scale production using solution processing methods. At the same time, the co-polymers derived from monomers of the present invention and electron donor monomers show low bandgaps, high charge carrier mobilities, high external quantum efficiencies in BHJ solar cells, good morphology when used in p/n-type blends e.g. with fullerenes, high oxidative stability, and a long lifetime in electronic devices, and are promising materials for organic electronic OE devices, especially for OPV devices with high power conversion efficiency.

#The units of formula I are especially suitable as (electron) donor unit in both n-type and p-type semiconducting compounds, polymers or copolymers, in particular copolymers containing both donor and acceptor units, and for the preparation of blends of p-type and n-type semiconductors which are suitable for use in BHJ photovoltaic devices.

#The polymers of the present invention in particular show good device performance, maintaining a high fill factor with thick coating (with a thickness >150 nm), and excellent environmental stability including thermal and photo stability.